How to Make It
Bring a large pot of water to a boil over high. Stir in farro and bring to a simmer. Reduce heat to medium-low; cook, uncovered, stirring occasionally, until tender, about 20 minutes. Drain and place in a large bowl.
While farro cooks, heat 1 tablespoon oil in a large skillet over medium. Add sweet potato, ¼ cup water, and ¼ teaspoon salt; cover and steam for 5 minutes. Uncover and continue to cook, stirring occasionally, until water evaporates and sweet potato is tender and browned, 10 to 12 minutes. Transfer to bowl with farro.
Heat 1 tablespoon oil in same skillet over medium. Add shallot and cook, stirring often, until softened, 3 to 4 minutes. Add pomegranate juice; cook, stirring occasionally, until reduced to ½ cup, 8 to 10 minutes. Whisk in vinegar, mustard, pepper, and remaining ¾ teaspoon salt. Remove from heat and gradually whisk remaining ¼ cup oil into dressing.
Add ¾ cup dressing to farro mixture and toss to coat. Add spinach and fennel; toss gently. Divide among 4 bowls and drizzle with remaining dressing. Top with cheese and garnish with fennel fronds.